Thread-cutting tool.



B. BORDEN.

THREAD CUTTING TOOL.

APPLICATION FILED DBO. 7, 1909.

1,076,188. Patented 0013.21, 1913.

narran srnrns Parana" formen.

BRADFORD BORDEN, 0F TORONTO, ONTARIO, VCANADA, ASSIGNOR TO THE BORDEN COMPANY, 0F WARREN, OHIO, A CORPORATION 'OF'OI-IIO; 1 1

THREAD-cumino Toon Y Specification of Letters Patent.

Application led December 7, 1909. Serial No. 531,791.

To all 'whomz't may concern Be it known that I, BRADFORD BORDEN,

of Toronto, Province ofOntario, Canada, have invented certain new and useful Improvements in Thread-Cutting Tools; and

I do hereby declare the following to be a full, clear, and eXact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

In an application for patent led by me September 23, 1908, Serial No. 454,333, I disclosed an adjustable die-stock or to-ol for cutting tapered threads, which too-l is capable of being employed without the use of lead screws, and without the use of workholders or other means for locking it to the pipe or article to be threaded.

The objections to the use of lead screws and work-holders are many, and even when it has been sought to dispense with lead screws it has been necessary heretofore to employ a frame or work-holder and the equivalent of a lead screw for insuring continued engagement between the chasers and the work. It has been sought to initiate this engagement by forming the threads in the throats of the chasers on a more abrupt taper than the main cutting threads, but this has not proved wholly successful, owing,

primarily, to the fact that the threads in the throat are formed on such a pronounced taper as to be incapable of exerting sufcient hold on the pipe when the main cutting threads begin to act to insure the retention of the tool against the work without the aid of al lead screw or its equivalent; and it is also due to the further fact that the chasers recede while the operator is endeavoring to bring about their engagement with the work.

The primary object of my invention is to do away with all means, extraneous of the chasers themselves, for initiating and con-y tinuing the engagement between the chasers and the work. This I am ena-bled to accomplish primarily by forming the chasers with main cutting threads on a diHerent vpla-ne from the threads in the throats and having a relatively pronounced step-upfrom the initially acting threads to the main threads, with the result that the threads in the throats will be capable, unaided, of holding the tool to the work as against the increased' resistance offered by the'main threads, when the step-up is made. I am further enabled to accomplish the stated result by postponing the recession of the chasers until the main threads take hold of the work. In other words, the chasers have a series Of threads, in their throats, which willreadily take hold lof the pipe and act like a roughin tool and form utters into which the Steppe -up main threa s-will follow atl correct pitch and with less resistance,'the recession of the chasers being deferred until the main threads act on suiiiciently far to insure engagement withk the pipe with the same facility that the dies or chasers of a bolt-'stock engage the work, and the number of threads in engagement 'withi the pipe by the time the main or stepped-up threads are brought into action, effectively hold the pipe as against the increased resistance oifered by the main threads. VAnd a further object of the invention is to enable the chasers to be thrown out of action at any stage in the' cutting operation. A

The invention will be hereinafter fully set forth and particularly pointed out in the claims.

In the accompanying drawings, Figure 1 is an end elevation. Fig. '2 is aside view. Fig. 3 is a diagrammatic View. Fig. l is a view of the inner face of one of the posts.

In the accompanying drawing, l designates a rotatable and longitudinally'movable chaser carrier, and 2 a series ofradiallyarranged chasers each of which is shown Patentedoet. ai, i913.

as having a lug 3 for engaging a cam groove 4.- of a chaser engaging plate 5 which is rotatably mounted on the front of the chaser carrier, and has detachably connected there-V to a second plate G after themanner contemplated by Letters Patent No. 862,876,

issued to `W. A. Neracher and myself on through` openings in the latter `andv are formed on their inner opposite' faces with diagonal guideways 8y to take in the laterally projecting lugs 9 of the second plate 6, These posts are connected at their outer ends, forward of the Chaser Carrier, by a cross bar 10, which is extended at right angles to the axis of the tool.

To the center of the bar 10 is pivotally secured the shank of a stop 12, which latter is shown in the form of a flat plate of such length as to span the end of any pipe within the range of the tool. The stop may be detachably secured to the cross bar by any suitable means, such as a screw 18. This stop at its inner end is designed to be about midway the length of the Cutting ends of the several chasers, that is, it terminates at some point intermediate the inner and outer ends of the threaded portions of the Chasers. In consequence, the stop at the beginning` of the threading operation is well within the plane of the chasers, and as the Chaser carrier is revolved the stop is caused to turn with it, being carried around by t-he chasers between which its ends project. As the threading operation progresses, however, and `by the time the Chasers have well taken hold of the pipe, the stop engages, or is engaged by, the end of the pipe, and the pressure of theJ latter against the stop, acting through cross bar 10, holds posts 7 from travelino longitudinally with the Chaser carrier. Tie relative movement between the Chaser carrier and the posts results in controlling the rotation ot' the Chaser-engaging plate, independently oct its rotation with the Chaser carrier, and hence the gradual recession of the chasers. Until this independent movement is b-egun the chasers are xedly held against recession, the posts being idle preventing any turning of the Chaser-engaging plate, vand it is one of the principal objects of my invention to defer this independent movement of the Chaser-engaging plate until a predetermined point in the cutting operation. This enables the chasers to take hold of the pipe before they begin to recede. According to the means shown the nonrecession of the chasers is due to the fact that the stop cannot engage with or be engaged by the pipe until after the cutting operation has progressed to a certain extent. It is not my purpose, however, to confine myself to this particular means for obtaining the desired result, since manifestly the same end may be attained by any means which, while allowing for the gradual recession of the chasers, will hold the latter against receding during the early stages otl the cutting operation.

I have shown each of the posts 7 as having a single diagonal wall 14 for co-acting with lugs 9, and a second, snort diagonal wall 14a opposite the upper end of wall lil. This second wall 14 forms, in conjunction with wall 14:, means for acting on lugs 9, as

the posts are moved inward-ly, to properly position the several chasers for the beginning of the cutting operation. Once the posts are moved outwardly sutliciently far to Clear walls 14a from lugs 9, the chasers may be thrown out of operation at any stage by simply tapping the laterally projecting handle of the Chaser-engaging plate. course, the wall 11ia may be extended to parallel, throughout its length, the wall 14, as shown in the before noted patent, but the advantage of being able to throw out the chasers at any stage of the operation will not then be present.

For the purpose of initiating the engagement between the chasers and the pipe without the use of work-holders or lead screws, I torni the cutting end of each Chaser with a series of initially acting threads 15 which are designed to take hold of the pipe and draw the tool thereon betere the chasers begin to recede. I also form each of the chasers with a second series or main cutting threads 1G on a different plane and preferably oi' greater depth than threads 15, which latter are preferably straight. In stating that the main threads are on a different plane from the initially-acting threads, I refer to the roots or base line of the threads i both series and not to the edges of the threads. I have shown the second series as tapered, but whether tapered or straight is immaterial, although better results are obt-ained by making them on a taper. The initially-acting threads act on the pipe in a manner similar' to a roughing tool, and they clut gutters into which the main threads will follow, enabling the latter to proceed at the correct pitch and with less resistance. The threads 16 are in-set relatively to the threads 15, with a step-up between the threads ot the two series. By this construction I am enabled to readily take hold of the pipe and cut gutters therein with a suiiicient number of threads equally in action to otlset the resistance of the main threads. Coincidently with the engagement of the second series o'j threads with the pipe the chasers begin to recede. According to the means shown this occurs when the stop contacts with the pipe. It, however, there were a. relative movement between the posts and the Chaser carrier 'from the start of the threading operation, as for instance, in a tool like that oi Patent No. 862,876, wherein the posts are mounted on a` work-holder, it would be necessary to form the outer ends of the guideways of the posts straight, so that for short distances such guideways, while allowing of a relative movement between the chaser carrier and the posts, would not allow or produce any independent rotation of the Chaser-engaging plate until after the cutting operation had progressed to' a certain extent. But regardless of the means employed for deferring the retraction of the chasers, the engagement with the pipe is initiated While the chasers are held against retraction. The threads of the second series Will cut to a greater depth than threads 15 because they are cut on an inward taper or are in-set to a greater extent than the initially-acting threads. Once this second series of threads comes into action the recession of the chasers is inaugurated and Will continue throughout the cutting operation. For the purpose of increasing the range of efhciency of the tool l prefer to form each of the chasers With cutting teeth on both ends, but this idea is old in the art.

Bly present invention may be employed for cutting straight threads and also, Within certain limits, for cut-ting tapered threads Without receding the chasers. To out a continuous straight thread it is only necessary to remove stop l2, but, if desired, cross bar 10 may be also removed. The posts act through the plate 6 to lock the chaser-engaging plate when the tool is used to cut straight threads. Under like conditions l may cut tapered threads by employing chasers having their cutting threads formed on a taper, but in such instances the length of the thread cut corresponds to the Width of the chaser.

The advantages of my present improvements will be apparent to those skilled in the art.

I claim as my invention vl. A tool for cutting tapered threads comprising, in combination, a chaser carrier, a series of radially-arranged chasers, means cooperating With said chasers for controlling their recession during the cutting operation, and means for rendering the last mentioned means effective to enable the chasers to begin their recession after the cutting operation has progressed toa predetermined point.

2. A to-ol for cutting tapered threads co1nprising, in combinatio-n, a chaser carrier, a series of radially-arranged chasers, a single element common to all the chasers to control the uniform recession thereof, and means cooperating With said single element arranged relatively to the chasers toallow them to begin their recession after the cutting operation has progressed to a predetermined point. y 8. A tool for cutting tapered threads comprising, in combination, a chaser carrier, a series of radially arranged chasers, a single element common to all the chasers to control the uniform recessionv thereof, means cooperating With said single element to control the same, and means for rende-ring the last mentioned means effective to en- I able the chasers to begin their recession after the cutting operation has progressed to a predetermined point.

4. A tool for cutting tapered threads comv prising, 1n combination, a chaser carrier, a

series of radially arranged chasers, a single element common to all the chasers to control the uniform recession thereof,'means cooperating with said single element to control the same, and means for acting on the last mentioned means to enable the chasers to begin their recession after the cutting operation has progressed to a predetermined point.

5. A tool for cutting tapered threads, comprising, in combination, a rotatable and longitudinally-movable chaser carrier, a series of radially arranged chasers, a chaser en gaging plate rotatable With and independently of said chaser'carrier, means for controlling the independent rotation of said plate, said means being rotatable With said chaser carrier, and means for acting on said last mentioned means to enable the chasers to begin their recession after the cutting operation has progressed to a predetermined point.

6. A tool for cutting tapered threads comprising, in combination, a rotatable and longitudinally movable chaser carrier, a series of radially arranged chasers, a chaser engaging plate rotatable with and independgaging plate rotatable with and independ-V ently of said chaser carrier, a post for controlling the independent rotation of said plate, said post being rotatable with said chaser carrier, and means with which the pipe or article being threaded is designed to engage for acting on said post, after the cutting operation has progressed to a predetermined point, to prevent the postpfrom traveling longitudinally With the chaser carrier.

8. A tool for cutting tapered threads comprising, in combination, a rotatable and longitudinally movable chaser carrier, a series of radially arranged chasers, a chaser entermined point, to prevent the post from traveling longitudinally with the chaser carrier.

9. ln a screw cutting device, the combination with a series of chasers, each. formed with a cutting 'f'ace having a series of threads in its throat and a series of main cutting threads, the roots or base lines of the threads oft the two series being on different planes, and the main threads steppedup from the throat threads, of a member movably supporting said chasers in such manner that they may retract during the cutting operation, and means whereby the retraction is controlled, the length of the throat threads being sufficient after initially gripping the work, to hold the device'to the latter against the resistance in stepping-up to the main threads, the burden of forming the threads on the work being taken up by the main threads. i

10. ln a scre.T cutting device, the combination with a series of chasers, each formed with a Cutting face having a series of threads in its throat, and a series of main cutting t-hreads, the roots or base lines of the threads of the twoy series being on dif'- ferent planes, and the main threads steppedup from the throat threads, of a member' movably supporting said chasers in such manner that they may retract during the cutting operation, means whereby the retraction is controlled and means for rendering the last mentioned means effective after the throat threads have gripped the work. y

ll. In a screw cutting device, the combination, with a series oil chasers, each formed with a cutting face having a series of threads in its tncat and a series of main cutting threads, the roots or base lines of the threads of the two series being on different planes, and the main threads steppedup from the throat threads, of' a member ymovably supporting said chasers in such manner that they may retract during the cutting operation, means whereby the retraction is controlled and means for rendering the last mentioned means effective as the main cutting threads grip the work.

12. In a tool for cutting taiv ered threads, the combination with a rotatable and longitudinally movable chaser carrier, of a series of chasers mounted in such carrier, each chaser having a series of threads for initiating the engagement between the chasers and the pipe to be threaded and also having a second series of threads on a diierent plane from the first mentioned threads, means for controlling the recession of the Chasers, and means for rendering the last mentioned means effective to permit the chasers to begin their recession coincident with the engagement with the pipe of the second series of threads.

13. ln a tool for cutting tapered threads,

the combination with a rotatable and longitudinally movable Chaser carrier, of a series of chasers mounted in the carrier, each chaser having a series of straight threads for initiating the engagement between the chasers and the pipe to be threaded and also having a second series of 'threads on a different plane Jfrom the straight threads, means for controlling the recession of the chasers, and means for rendering the last mentioned means effective to permit the chasers to begin their recession coincident with the engagement with the pipe of the second series of threads.

14. ln a tool for cutting tapered threads, the combination with a rotatable and longitudinally movable Chaser Carrier, of a serios of chasers mounted in the carrier, each Chaser having a series of straight threads for initiating the engagement between the chasers and the pipe t0 be threaded and also having a second series off threads cut on a taper, means for controlling the recession of the chasers, and means for rendering the last mentioned means effective to permit the chasers to begin their recession coincident with the engagement with the pipe of the y series of tapered threads.

l5. ln a tool for cutting tapered threads, the combination with a' rotatable and longitudinally movable chaser carrier, of a series of chasers mounted in such carrier, each Chaser having a series of threads for initiating the engagement between the chasers and the pipe to be threaded and also having a second series of threads, such second series being cut on a taper, means for controlling the recession of the chasers, and means for rendering the last mentioned means effective to permit the chasers to begin their recession coincident with the engagement with the pipe of the second series of threads.

16. In a tool for cutting tapered threads, the combination with a rotatable and longitudinally movable chaser carrier, of a series of chasers mounted in the carrier, a single element Common to all the chasers to control the uniform recession thereof, means rotatable with the chaser carrier for making effective the action of said single element as the Chaser Carrier travels over the Dipe to be threaded, and pipe engaging means for preventing the last mentioned means from traveling longitudinally with the housing after a predetermined point in the travel of such Chaser carrier, such pipe engaging means being so positioned relatively to the chasers that engagement with the pipe will not occur until after the chasers have talren hold of the pipe.

17. ln a tool for cutting tapered threads, the combination with a rotatable andA longitudinally-movable Chaser Carrier, of a series of chasers mounted in the carrier, a

iso

Chaser engaging plate rotatable with and i11- dependently of said Chaser carrier, and means rotatable with the Chaser carrier, but not partalring of the longitudinal travel thereof, for Controlling the independent rotation of the Chaser-engaging plate and constructed to permit the latter to be moved to throw the chasers outwardly at any point during the Cutting` operation after the plate has been moved independently of its rotation with the Chaser carrier.

18. In a tool for cutting tapered threads, the combination with a rotatable and longitudinally movable Chaser carrier, of a series of Chasers mounted in the carrier, a Chaser engaging plate rotatable with and independently of said Chaser-carrier, and means rotatable with the Chaser-carrier, but not partaking of the longitudinal travel thereof, for effecting the independent rotation of the Chaser-engaging plate and constructed to permit the latter to be moved to throw the Chasers outwardly at any point during the Cutting operation after the plate has been moved independently of its rotation with the Chaser-carrier.

19. In a tool for cutting tapered threads, the combination with a rotatable and longitudinally movable Chaser Carrier, of a series of Chasers mounted in the carrier, a chaserengaging plate rotatable with and independently of said Chaser-carrier, said plate having a lateral projection, and a post rotatable with the Chaser-Carrier, but not partaking of the longitudinal travel thereof, said post having a diagonal wall with which said projection is designed to engage and by which the plate is forced in the direction to eect the recession of the chasers, said post permitting said plate to be turned to throw the chasers outwardly at any point during the Cutting operation.

20. In a tool for cutting tapered threads, the Combination with a rotatable and longitudinally-movable Chaser-carrier, of a series of Chasers mounted in the Carrier, a Chaser-engaging plate rotatable with and independently of said Chaser-carrier, said plate having a lateral projection, and a post rotatable with the Chaser-carrier, but not partaking of the longitudinal travel thereof, said post having a diagonal wall with which said projection is designed to engage, and also having a second diagonal wall paralleling the first mentioned wall for a portion of the length thereof.

2l. In a tool for cutting tapered threads, the combination with a rotatable and longitudinally movable Chaser-Carrier, of a series of chasers mounted in such carrier, a single element common to all the chasers, a post having a `diagonal guideway for acting on said single element, to effect the simultaneous recession of the chasers, a Cross-member connected to said post, and a stop secured to said cross-member and extendingv into the chaser carrier to a point'intermediate the ends of the cutting faces of the chasers to engage with the pipe to be threaded to effect the recession of the chasers after they have taken hold of the pipe.

22. In a tool for cutting tapered threads,

the combination with a rotatable and longitudinally -movable Chaser-carrier, of a series of chasers mounted in such Carrier, a single element common to all the chasers, a post having an interlocking engagement with said single element to effect the. simultaneous recession of the chasers, -a crossmember connected to said post, and a stop secured to said cross-member and extending into the Chaser carrier to a point intermediate the ends of the cutting faces of the chasers to engage with the pipe to be threaded to effect the recession ofthe chasers afterl they have taken hold of the pipe, said single element ybeing capable of being moved out of engagement with said post to throw the chasers outwardly at any point during the cutting operation.

23. The combination with a Chaser-carrier, of a series of radially-movable chasers, 'a cam plate engaging said chasers and carrying a laterally projecting lug, a post mounted in the Y Chaser-carrier and having a'wall formingV a diagonal guideway,vand also havinga second wall paralleling the first mentioned wall near one end thereof, a cross-bar carried by said post, and a stop carried by said cross- Copies of this patent may 'be obtained for five cents each, by addressing the Commissioner of Patents Washington, ID. G. 

